Citrus fruits are harvested by hand picking. In general, the conventional harvesting method for picking citrus fruit from low density trees uses pallet tubs, pick sacks and expensive in-grove vehicles with booms for collecting and removing the picked fruit from the grove.
More specifically, the picked fruit is placed into a sack carried over the shoulder of the fruit picker. The citrus fruit picker carries the full sack of fruit to a pallet tub having, for example, a ten box capacity. The fruit picker empties about sixty (60) pounds of picked fruit from the sack into the pallet tub and then returns to the next tree with an empty sack to repeat the cycle.
The pallet tub is a means of collecting picked fruit in citrus groves. A large number of pallet tubs are placed in spaced relationship to one another throughout the grove in rows adjacent the trees to reduce the walking distances involved to empty a fruit filled sack. A full pallet tub weighs about 900 lbs. and is emptied by means of a field truck with a boom. The field truck is called a loader or goat.
The current method for harvesting, collecting and removing fruit from citrus groves containing smaller or younger trees requires pick sacks, pallet tubs and a loader to lift and empty the full pallet tubs and to then reposition the empty pallet tubs. The process of collecting and removing the picked fruit from the grove with the loader is called "road-siding". The loader is a modified truck equipped with a rotatably mounted hydraulic boom specifically designed to lift and empty a fruit filled pallet tub into the loader's bed. Alternatively, the loader may be modified to straddle the pallet tubs and either lift or place those tubs through a specialized fork lift type mechanism, as shown for example in U.S. Pat. No. 3,666,126. The loader's bed is supported by a hydraulic scissor lift which raises and pivots the bed to empty the load of fruit into a trailer. The trailer hauls the fruit to the processing plant.
The distance between the respective pallet tubs in rows adjacent the citrus trees is determined by the amount of citrus fruit on the trees to be picked between the pallet tubs. Citrus groves with high fruit density trees, about 1,100 oranges per tree, require the tubs to be relatively closely spaced to one another. This close spacing increases the efficiency and productivity of a picker by reducing the walking distance from the tree to the pallet tub. Conversely, young citrus groves with low fruit density, about 8 to 12 oranges per tree, result in the tubs being spaced further apart. The increased spacing requires the picker to walk with a partially full sack of fruit greater distances between pallet tubs. The cost of operating the loaders does not permit the driver to work along with small groups of pickers for picking low density trees. The equipment would either be idle or would inefficiently be continuously moving partially filled pallet tubs as the pickers move from tree to tree.
A ten box pallet tub holds about 2,200 oranges which represents the average production from two trees that are eight to ten years old. Citrus groves with young trees that are two to four years old will average about eight to twelve oranges a tree per year. A citrus grove with young trees with an average fruit density of ten oranges a tree requires a picker to harvest about two hundred and twenty trees to fill one pallet tub. Citrus trees are spaced about 16 feet apart requiring a picker to walk about 3,520 feet to fill one pallet tub. Citrus growers are charged two to three times the normal picking rate to have their low density, young trees picked. As a result, most growers cannot afford to justify the additional cost to have the fruit picked from their young trees until the trees reach a minimum production of about 30 oranges per tree.
A series of freezes during the past eight years substantially reduced the number of high density groves and precipitated a sharp increase in the number of newly planted citrus groves. Changes in the Immigration Act and the substantial reduction in the number of high density citrus groves has made it extremely difficult and expensive to harvest citrus fruit from low density young citrus trees.
These freezes have caused the citrus industry to reconsider the planting configuration utilized for new trees. Several groves have been planted where the trees are planted more closely together in the rows and where the aisles between rows are narrower. For example, groves have been planted with trees spaced eight feet apart with fifteen foot wide aisles. This increased density is believed to provide some protection against frost conditions and reduces the walking distances required for picking these young trees having a low fruit density. However, this increased tree planting density also creates picking problems because it is difficult to move and position the bins and difficult to maneuver and use the loader.
Some other machines to mechanize the harvesting of citrus fruit have been developed. However, these machines are best utilized on taller trees having a high fruit density.
For example, U.S. Pat. No. 3,878,957 discloses a fruit harvesting apparatus with a rotatably mounted extensible hollow boom on the front section of a vehicle. A man supporting bucket is carried at the outer end of the boom. The trough around the bucket guides the fruit picked by a man therein into the outer or distal end of the boom. Three telescopically connected extensible ducts within the boom extend from the trough to a hopper. Subatmospheric pressure is used in the extensible ducts to pneumatically convey the fruit through the extensible boom to the hopper for bulk storage.
The fruit harvesting apparatus disclosed in U.S. Pat. No. 3,878,957, which is exclusively licensed to the assignee of the present invention, will not allow multiple persons simultaneously to use the bucket to harvest citrus fruit. As the man supporting bucket of this patent moves closer to the ground, the radius of the flex duct connecting the trough to the outer opening of the duct at the distal end of the boom becomes increasingly smaller. When the bucket sits on the ground, the small radius of the flex duct restricts the opening for the fruit and limits the number of oranges that can flow into the pneumatic duct system. As a result, the production from multiple persons harvesting fruit and placing that fruit in the trough of the bucket at ground level will clog the flex duct entry thereby preventing the efficient use of the boom machine for picking small young trees. In addition, the use of the extensible boom is relatively complicated, and the boom machine is more expensive to build and maintain than the present apparatus.
This problem with the capacity and use of the boom machine was at least partially addressed by providing several additional flexible pneumatic hoses extending from the hopper. Pickers could walk beside the loader and place picked citrus fruit into the additional hoses. However, these hoses were awkward to use, were heavy to handle, and usually become clogged with citrus fruit.
Other examples of boom type harvesting machines are described and illustrated in U.S. Pat. Nos. 2,450,152; 2,821,312; 2,973,112; 3,329,290; 3,523,404 and 3,633,336.